The present invention is directed to a brake system for a vehicle, as well as to a method for operating a brake system, a braking pressure that is dependent upon a correction factor being adjusted by the brake system, the correction factor being produced by a characteristic curve between the correction factor and the transversal acceleration of the vehicle.
In response to a vehicle""s transversal accelerations, it can happen, in the vehicle""s brake system, that the pistons of wheel-brake cylinders are pushed into these cylinders (so-called variation in the air gap). To push the pistons out of the wheel-brake cylinders again, a brake medium must be pressed into the wheel-brake cylinders. This degrades the braking performance. To lessen this influence that degrades the braking response, German Patent DE 197 12 889 describes a method for correcting the braking pressure.
The object of the present invention is to improve a vehicle""s braking performance.
This objective is achieved in accordance with the present invention by a method pursuant to Claim 1 and Claim 2, as well as by a brake system pursuant to Claims 8 and 9, and by a control unit for a brake system pursuant to Claim 10. In this context, a braking pressure that is dependent upon a correction factor is adjusted by the brake system, the correction factor being generated by a characteristic curve having a substantially continuous, first derivative between the correction factor and the transversal acceleration of the vehicle, and/or the correction factor being generated by a characteristic curve which is between the correction factor and the transversal acceleration of the vehicle and whose range includes an ascent that is dependent upon the vehicle""s transversal acceleration.
A vehicle brake system in accordance with the present invention, which is able to adjust a braking pressure that is dependent upon a correction factor, has a memory including a characteristic curve between the correction factor and the transversal acceleration of the vehicle, the first derivative of the characteristic curve between the correction factor and the transversal acceleration of the vehicle being, in particular, substantially continuous, and/or the characteristic curve which is between the correction factor and the transversal acceleration of the vehicle having at least one range that includes an ascent that is dependent upon the vehicle""s transversal acceleration.
A control unit for the brake system of a vehicle in accordance with the present invention for generating manipulated variables, which are dependent upon a correction factor, for the brake system to adjust a braking pressure, has a memory including a characteristic curve between the correction factor and the transversal acceleration of the vehicle, the first derivative of the characteristic curve between the correction factor and the transversal acceleration of the vehicle being, in particular, substantially continuous, and/or the characteristic curve which is between the correction factor and the transversal acceleration of the vehicle having at least one range that includes an ascent that is dependent upon the vehicle""s transversal acceleration.
In an advantageous embodiment of the present invention, the characteristic curve has at least one first range and/or at least one second range including a correction factor that is independent of the vehicle""s transversal acceleration.
In another advantageous embodiment of the present invention, the characteristic curve between the first range and the second range has a third range having a correction factor that is, in particular, linearly dependent upon the vehicle""s transversal acceleration.
In another advantageous embodiment of the present invention, the characteristic curve has a range between the first range and the third range that includes an ascent that is dependent upon the vehicle""s transversal acceleration, the correction factor advantageously being dependent upon the square of the vehicle""s transversal acceleration.
In yet another advantageous embodiment of the present invention, the characteristic curve has a range between the range and the third range that includes an ascent that is dependent upon the vehicle""s transversal acceleration, the correction factor advantageously being dependent upon the square of the vehicle""s transversal acceleration.
One exemplarily embodiment of the present invention provides a filter for filtering a measured value of a vehicle""s transversal acceleration. In accordance with this embodiment, a filtered value for the transversal acceleration is the input value for characteristic curve designated above.